In many messaging, voice calling, and instant messaging applications, presence has been a key enabler and driver of messaging services. However, the presence status in such services has typically been limited to a user specifying their availability status by manually selecting options such as online, busy, away, etc.
Further, presence status in such services is often made accessible only to users within that service, wherein the users of the service have to be signed on and be approved by the user to be able to view their presence status.
In the mobile phone industry, presence as it has been used in the instant messaging applications has had limited usability as often users are always considered online, or in other words accessible on their mobile device. Further, a very small percentage of users are actively signed on to an instant messaging service on their mobile device at any given time.
Also due to the fragmentation in the mobile industry, extending the usability of presence in the mobile context poses a significant challenge for the industry.
Additionally, due to privacy concerns, extending a user's presence more broadly to everyone or even to all of their contacts is an issue that the industry has not been able to address.
In summary, usability of presence has been limited to desktop applications, where it is primarily integrated with instant messaging applications, and in the mobile context, usability of presence has been significantly diminished due to technological and other constraints imposed by the industry.